1. Field of the Invention
The present invention relates to bonding compositions suitable for dental use. More precisely, the invention relates to bonding compositions suitable for dental use, which exhibit good adhesiveness between a tooth and restorative dental materials in dental treatment, and which are for preventing the growth of cariogenic bacteria in the bonded area.
2. Description of the Related Art
In dental treatment, where partial defects in teeth are restored through prosthesis with restorative dental materials such as, for example, composite resins, monomers, metal alloys and ceramics for dental restoration, dental bonding compositions are often used. However, when such a restorative dental material is directly bonded to the surface of a tooth, it does not exhibit satisfactory bonding strength since it is not adhesive by itself. As a result, the restorative dental material as directly bonded to a tooth will peel off, or, as the case may be, bacteria will penetrate into the bonded interface between the tooth and the restorative dental material to cause secondary caries and odontitis.
In order to solve this problem, various dental bonding methods which include previous application of some tooth surface treating agents to defective teeth to be restored have heretofore been described. Some reports disclose that such tooth surface treating agents improve the bonding strength between a tooth having been pre-treated with any of them and a restorative dental material applied to the surface-treated tooth. For example, (1) Journal of Dental Research Vol. 34, pp. 849-854, 1955 discloses that some acid etching primers improve the bonding strength of restorative dental materials to tooth enamel; (2) Journal of Dental Research, Vol. 63. pp. 1087-1089, 1984 discloses that a primer composition comprising glutaraldehyde, 2-hydroxyethyl methacrylate (hereinafter referred to as HERA) and water enhances the bonding strength of restorative dental materials to tooth; (3) JP-A-62-223289 discloses that a primer as prepared by adding an acid such as maleic acid, nitric acid or p-toluenesulfonic acid to an aqueous solution of HEMA improves the bonding strength of restorative dental materials to tooth enamel and tooth; (4) JP-A-1-113057 discloses that a primer as prepared by adding a salt of an acid to an aqueous solution of HEMA improves the bonding strength of restorative dental materials to tooth enamel and tooth; and (5) Materials and Instruments for Dental Use, Vol. 9. pp. 65-73, 1990 discloses that a primer as prepared by adding a monomer having an amino acid residue such as N-acryloylaniline or the like to an aqueous solution of HEMA improves the bonding strength of restorative dental materials to tooth enamel and tooth. In addition, (6) JP-A-3-240712 discloses a dental bonding composition as prepared by adding a polymerizable monomer having an acidic group and a curing agent to an aqueous solution of HEMA; and (7) JP-A-4-8368 discloses that adding an amino compound to the dental bonding composition in (6) enhances the ability of the composition to improve the bonding strength of restorative dental materials to teeth.
In particular, a dental bonding method of using a self-etching adhesive primer is an extremely excellent technique, as being easy to perform and provides a high bonding strength to the tooth. The adhesive primer for use in the method comprises an acid (including acidic monomers), a hydrophilic monomer and water, and the method of using it comprises applying the primer to the surface of a tooth and directly applying a bonding material thereto without washing and drying the primer-coated tooth.
However, the self-etching adhesive primer which does not require washing with water is problematic in that the polymerizable monomer will partly remain in the surface layer of tooth even though most of the solvent such as water and the like could be removed through drying with a dental air syringe after its application. The remaining monomer may be polymerized and cured together with the overlaid bonding material by irradiation of light. However, the adhesive primer contains low polymerizable monomers such as hydrophilic monomers and acidic monomers, which could not be polymerized all at once. In order to enhance its polymerizability, some means of improving the adhesive primer have heretofore been tried by adding thereto a photopolymerization initiator, which, however, could not produce the intended effect up to the present. As a result, the polymerization of the monomers in the bonding material (including the adhesive primer) applied to the surface of a tooth is insufficient, and, in a certain period of time after the restoration of the tooth with a restorative dental material, a crevice is formed between the tooth and the butted material to cause marginal leakage, or the butted material is peeled off. Such problems with the adhesive primer have heretofore been often pointed out. In particular, it is said that the problems are remarkable when the bonding material is irradiated by light for a short period of time.
Improving the polymerization curability of the adhesive primer end the bonding material could be attained in some degree by increasing the amount of the photopolymerization initiator in those compositions. Increasing the amount of the initiator too much in those compositions is problematic in that the initiator remaining in the cured products of the compositions will be much released out, since the initiator has no polymerizable group, and, in addition, the mechanical strength of the cured products is lowered and the cured products are discolored with the lapse of time. In that condition, aesthetic tooth crown repairing is impossible. For these reasons, adding too much initiator to the compositions is impracticable.
There is still another problem of secondary caries and odontitis that may be caused by the penetration of bacteria into the bonded interface between tooth and the restorative dental material applied thereto, in addition to the bonding durability failure in the bonding material used. The problem is often pointed out as serious.
For preventing the penetration of bacteria into the bonded interface, antibacterial dental bonding materials have been proposed. For examples JP-A-1-17107 discloses dental cement that contains an antibacterial agent. JP-A-2-16176 and B-198723 disclose a pre-treating agent for dental use that contains a quaternary alkylammonium salt. In these, they do not specifically refer to the antibacterial property of the pre-treating agent, but the quatemaryalkylammonium salt used will have antibacterial ability. However, the antibacterial agent and the quaternary alkylammonium salt have no polymerizable group, and will be therefore released out into the mouth after the dental bonding composition comprising any of them has been polymerized and cured on a tooth. Prior to their dental application, therefore, the antibacterial agent and the quaternary alkylammonium salt require complete safety evaluation. Another problem with them is that the antibacterial agent and the quaternary alkylammonium salt do not exhibit the antibacterial ability for a long period of time.
JP-A-6-9725 and 7-215814 disclose dental compositions containing an antibacterial polymerizable monomer and an acid group-having polymerizable monomer. The antibacterial property as referred to in these is the non-releasing antibacterial property of the polymerized (or cured) products of the dental compositions. Here, the cured products do not release the antibacterial component from them. These publications indicate that the cured products as formed through copolymerization of the antibacterial polymerizable monomer and the other monomer exhibit the antibacterial ability on their surface. Specifically, in the cured polymer products of the dental compositions proposed, the unpolymerized antibacterial compound is exposed out on the surface of the cured polymer, and it may attenuate the bacteria having adhered on the surface of the cured products, but could not kill the bacteria existing in the fine structure of the bonded interface of tooth tubules.
One means of solving the problem has been proposed in JP-A 8-157318, which discloses an antibacterial adhesive primer comprising an antibacterial polymerizable monomer, an acid group-containing polymerizable monomer, an alcoholic hydroxyl group-containing polymerizable monomer, water and a polymerization catalyst.
The technique proposed is characterized in that an antibacterial polymerizable monomer is added to the adhesive primer for killing bacteria in and around teeth while, at the same time, attaining decalcification of teeth, and that the polymerized and cured product of the primer composition exhibits a non-releasing antibacterial ability on its surface. Therefore, this is an extremely useful technique. However, the adhesive primer contains a large amount of slightly-volatile components such as the acid group-containing polymerizable monomer and the alcoholic hydroxyl group-containing polymerizable monomer. Therefore, the probability of contact between bacteria and the antibacterial polymerizable monomer in a resultant product is low, and the adhesive primer could not satisfactorily express the antibacterial ability. In addition, when cured on a tooth the adhesive primer gives a layer of a copolymer of the antibacterial polymerizable monomer and other polymerizable monomers in and around the bonded interface between its cured product and the tooth. However, since the proportion of other polymerizable monomers to the antibacterial monomer is large, the adhesive primer could not still produce a satisfactory antibacterial effect.
Greatly increasing the amount of the antibacterial polymerizable monomer or greatly decreasing the amount of the acid group-containing polymerizable monomer and that of the alcoholic hydroxyl group-containing polymerizable monomer in the adhesive primer could improve the antibacterial ability of the adhesive primer in some degree, which, however, is not practicable as greatly lowering the bonding force of the adhesive primer to a tooth.
A composition comprising an antibacterial polymerizable monomer and a volatile solvent is known. For example, as in JP-A-9-67546, an antibacterial polymerizable monomer may be added to an adhesive composition comprising a monomer capable of bonding to metal and a volatile solvent. However, the adhesive composition disclosed in JP-A-9-67546 is directed to modification of the surface of metal, and nothing is referred to therein that relates to a technique of killing bacteria in and around a tooth. The present inventors tested the compositions of the examples disclosed in JP-A-9-67546, but the compositions did not have high bonding strength to a tooth.
JP-A-10-236915 discloses an antibacterial caries-detecting liquid that comprises an antibacterial polymerizable monomer, a dye, and water and/or a water-miscible solvent. Basically, this liquid is applied to a tooth before the affected tooth is removed from the tooth with a cutting tool, thereby killing the cariogenic bacteria that exist in and around the affected tooth while differentiating the affected-tooth from the non-affected healthy tooth, and the technique disclosed is very useful. However, most of the antibacterial polymerizable monomer in the antibacterial caries-detecting liquid is removed along with the affected tooth which is removed with a cutting tool. In that condition, a high concentration of the monomer could not be in and around the tooth treated with the liquid. Therefore, even though the liquid could kill the cariogenic bacteria existing in and around tooth, it is almost completely ineffective against the cariogenic bacteria that may penetrate into the restored area of a tooth, and therefore could not prevent the growth of the cariogenic bacteria penetrated into that area after treatment.
Accordingly, there remains a need for compositions and methods which overcome the problems described above.
It is an object of the present invention to provide bonding compositions suitable for dental use.
It us another object of the invention to provide bonding compositions which can inhibit the growth of cariogenic bacteria in the bonded area of a tooth when restored with a restorative dental material, thereby preventing secondary caries and odontitis around that area, and which can enhance the bonding strength, especially the bonding durability of the restorative dental material, to a tooth.
To accomplish the objects noted above, the present inventors have assiduously studied the problem of how to prevent the growth of cariogenic bacteria in the bonded area of tooth as restored with a restorative dental material and of how to entrance the bonding curability of a restorative dental material and a tooth as restored with the material, and, as a result, have discovered the following novel techniques.
Technique for Preventing the Growth of Cariogenic Bacteria
An antibacterial primer comprising a specific antibacterial polymerizable monomer and a volatile solvent is applied around the surface of a tooth, and then dried spontaneously or through dental air blowing so as to make a high concentration of the antibacterial, polymerizable monomer on the tooth surface, thereby killing the bacteria having adhered on the surface of tooth of the tooth. Thereafter, an adhesive composition that comprises an acid group-containing polymerizable monomer, a polymerizable monomer and a polymerization initiator is applied to the area of the tooth, and is cured along with the antibacterial monomer previously applied thereto, thereby forming an antibacterial polymer layer having a high concentration at the interface between the tooth and the bonding material. Bacteria that may penetrate into the bonded interface are killed by the antibacterial polymer layer, and the polymer existing in the bonded interface retains its antibacterial ability for a long period of time.
Technique of Enhancing Bonding Durability of Bonding Compositions
The adhesive composition described above is composed of two compositions, one being an adhesive primer that comprises an acid group-containing polymerizable monomer, a hydrophilic polymerizable monomer and water, and the other being a bonding agent that comprises a polymerizable monomer and a polymerization initiator. The adhesive composition of this type is a so-called self-etching adhesive component. The photopolymerization initiator in the bonding agent contains both an acylphosphine oxide compound and an xcex1-diketone compound. The adhesive primer is first applied to a tooth and is cured along with the bonding agent within a short period of time to form a hard cured layer on the tooth by which the bonding durability of the cured layer to a tooth is enhanced.
Based on the techniques as described above, the present inventors have discovered that the bonding compositions according to the present invention significantly prevent the growth of cariogenic bacteria in the bonded area between tooth and restorative dental material applied thereto and enhance the bonding strength, especially the bonding durability between tooth and a restorative dental material applied thereto, as compared with conventional bonding compositions.
Accordingly, the objects of the invention, and others, may be accomplished with an antibacterial bonding composition suitable for dental use, comprising:
(A) an antibacterial primer comprising (i) an antibacterial polymerizable monomer containing an ethylenic unsaturated group and at least one cationic group selected from the group consisting of ammonium bases, pyridinium bases and phosphonium bases, and (ii) a volatile solvent; and
(B) an adhesive composition comprising (i) a first polymerizable monomer containing an acid group, (ii) a second polymerizable monomer, and (iii) a polymerization initiator.
The objects of the invention may also be accomplished with an adhesive composition suitable for dental use, comprising:
(P) an adhesive primer comprising (i) a polymerizable monomer containing an acid group, (ii) a hydrophilic polymerizable monomer, and (iii) water; and
(Q) a bonding agent comprising (i) a polymerizable monomer, (ii) an acylphosphine oxide compound, and (iii) an xcex1-diketone compound.
The objects of the invention may also be accomplished with an antibacterial bonding composition suitable for dental use, comprising:
(A) an antibacterial primer comprising (i) an antibacterial polymerizable monomer containing an ethylenic unsaturated group and at least one cationic group selected from the group consisting of ammonium bases, pyridinium bases and phosphonium bases, and (ii) a volatile solvent;
(P) an adhesive primer comprising (i) a polymerizable monomer containing an acid group, (ii) a hydrophilic polymerizable monomer, (iii) water, and (iv) a polymerization initiator; and
(Q) a bonding agent comprising a (i) polymerizable monomer, (ii) a polymerizable monomer containing an acid group, (iii) an acylphosphine oxide compound, and (iv) an xcex1-diketone compound,
where the ratio of the acylphosphine oxide compound to the xcex1-diketone compound is 1:0.01 to 1:0.5.
The objects of the invention may also be accomplished with a composition suitable for dental use, comprising:
(a) an antibacterial polymerizable monomer containing an ethylenic unsaturated group and at least one cationic group selected from the group consisting of ammonium bases, pyridinium bases and phosphonium bases;
(b) an a polymerizable monomer containing an acid group;
(c) an additional polymerizable monomer; and
(d) a polymerization initiator.
The objects of the invention may also be accomplished with a method of providing an antibacterial coating on a tooth, comprising curing the composition described above on the tooth.
The objects of the invention may also be accomplished with a method of applying an antibacterial coating to a tooth, comprising:
applying to a tooth a first composition comprising (i) an antibacterial polymerizable monomer containing an ethylenic unsaturated group and at least one cationic group selected from the group consisting of ammonium bases, pyridinium bases and phosphonium bases, and (ii) a volatile solvent;
removing at least a portion of the volatile solvent;
applying to a tooth a second composition comprising (i) a first polymerizable monomer containing an acid group, (ii) a second polymerizable monomer, and (iii) a polymerization initiator; and then
curing the applied compositions.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description.
The term xe2x80x9cadhesive compositionxe2x80x9d as used herein refers to an adhesive for bonding a restorative dental material to a tooth, and this includes an adhesive primer that is applied to a tooth or to a restorative dental material prior to bonding the tooth and the material so as to enhance the bonding strength between the two. Specifically, the adhesive compositions in the invention encompasses any combination of two or more compositions that may be wrapped or packaged separately, for example, a combination of an adhesive primer and a bonding agent, or a combination of an adhesive primer and a resin cement.
The antibacterial polymerizable monomer for use in the invention has an ethylenic unsaturated group and at least one cationic group selected from the group consisting of ammonium bases, pyridinium bases and phosphonium bases. For example, generally used are antibacterial polymerizable monomers of the following general formulae (I) to (IV): 
wherein
R1=H or CH3,
R2=alkylene group having 2-25 carbon atoms,
X=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
a=0 or 1,
b=0 or 1, 
R3=H or xe2x80x94(V)cxe2x80x94R7xe2x80x94W,
R4, R5, R6=(V)cxe2x80x94R7xe2x80x94W,
V=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
R7=alkylene group having 1-25 carbon atoms,
W=H, CH3, OH or 
c=0 or 1,
Z=anion. 
wherein
R8=H or CH3,
R9=alkylene group having 2-25 carbon atoms,
X=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
d=0 or 1,
e=0 or 1, 
R10=H or xe2x80x94(V)fxe2x80x94R13xe2x80x94W,
R11, R12=(V)fxe2x80x94R13xe2x80x94W,
V=O, S, NH 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
R13=alkylene group having 1-25 carbon atoms,
W=H, CH3, OH or 
f=0 or 1,
Z=anion. 
wherein
R14=H or CH3,
R15=alkylene group having 2-25 carbon atoms,
X=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
g=0 or 1,
h=0 or 1,
R16, R17, R18=(V)1xe2x80x94R19xe2x80x94W,
V=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
R19=alkylene group having 1-25 carbon atoms,
W=H, CH3, OH or 
i=0 or 1,
Z=anion. 
wherein
R20=H or CH3,
R21, R22=alkylene group having 1-25 carbon atoms,
j=0 or 1,
k=0 or 1,
A=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
B1, B2,=xe2x80x94COxe2x80x94, xe2x80x94COOxe2x80x94, xe2x80x94OCOxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NHCOOxe2x80x94 or xe2x80x94OCONHxe2x80x94,
R23=xe2x80x94(V)pxe2x80x94R24Wxe2x80x2,
V=O, S, NH, 
xe2x80x94CH2Oxe2x80x94 or xe2x80x94OCH2xe2x80x94,
R24=alkylene group having 1-25 carbon atoms,
W1=H, CH3, OH, 
p=0 or 1,
Z=anion.
Specific examples of the compounds of formula (I) include the following: 
Specific examples of the compounds of formula (II) include the following: 
Specific examples of the compounds of formula (III) include the following: 
Specific examples of the compounds of formula (IV) include the following: 
Among these monomers, preferred are the antibacterial polymerizable monomers having an alkylene group with 10 or more carbon atoms, which exhibit good antibacterial properties. Such monomers include, for example, methacryloyloxydodecylpyridinium salts, methacryloyloxyhexadecylpyridinium salts, methacryloyloxydecyltriethylammonium salts, 4-hexadecylmethacryloyloxyethylpyridinium salts, methacryloylaxyethylhexadecylbipyridinium salts, methacryloyloxydodecyltrimethylphosphonium salts, methacryloyloxyoctadecyltriethylphosphonium salts, 4-methacryloyloxyethyldodecylpyrldinium salts, di(4-vinylbenzyl)hexadecylmethylammonium salts, di(methacryloyloxyethyl)dodecylmethylammonium salts, methacryloyloxyethyl(4-N-hexadecylpyridinylmethyl) succinate halides, etc.
In the antibacterial polymerizable monomers, the anions which are formally paired with the ammonium cation, the pyridinium cation and the phosphonium cation are not particularly limited. They include, for example, halides such as Fxe2x88x92, Clxe2x88x92, Brxe2x88x92, Ixe2x88x92; anions derived from inorganic acids such as PO43xe2x88x92, HPO32xe2x88x92, H2PO4xe2x88x92, Na2PO32xe2x88x92, Na2PO3xe2x88x92, SO42xe2x88x92, HSO4xe2x88x92, KSO4xe2x88x92, NO3xe2x88x92 etc.; anions derived from organic acids such as methanesulfonic acid, acetic acid, propionic acid, benzoic acid, phenol, p-toluenesulfonic acid, maleic acid, oxalic acid, citric acid, etc.; and also anions derived from polymerizable acidic compounds that will be mentioned hereinunder. They further include anions derived from polymerizable acids such as AlF63xe2x88x92, AsFexe2x88x92, BF4xe2x88x92, BiCl42xe2x88x92, BiCl32xe2x88x92, SbCl6xe2x88x92, SbF6xe2x88x92, PF6xe2x88x92, GaCl4xe2x88x92, InF4xe2x88x92, TiF62xe2x88x92, ZrF6xe2x88x92, FeCl4xe2x88x92, SnCl6xe2x88x92, etc. Halides are the preferred anions. These anions are paired with the cations, either singly or as combined.
One or more antibacterial polymerizable monomers may be used herein either singly or as combined, i.e., as a mixture. The amount of the antibacterial polymerizable monomer in the antibacterial primer may generally fall between 0.000001% by weight and 50% by weight, preferably between 0.001% by weight and 30% by weight, more preferably between 0.01% by weight and 10% by weight, based on the total weight of the primer. These ranges include all specific values and subranges therebetween, such as 0.0001, 0.01, 0.1, 0.5, 1, 2, 5, 15, 20 and 25% by weight, based on the total weight of the primer. The ranges described above, and those described below, include the endpoints unless noted otherwise.
In the present invention, the volatile solvent in the antibacterial primer has the ability to dissolve the antibacterial polymerizable monomer. The solvent includes, for example, volatile organic solvents having a boiling point at ordinary pressure of not higher than 250xc2x0 C., water, and mixtures thereof. Examples of volatile organic solvents include alcohols such as methanol, ethanol, 2-ethylbutanol isopropanol; ketones such as acetone, methylethyl ketone, 2-butanone, 3-pentanone; ethers such as diethyl tetrahydrofuran; as well as ethyl acetate, toluene, xylene, p-cymene, hexane, octane, pentane, methylene chloride, 1,2-dichloroethane, methyl methacrylate.
Of those, preferred are volatile organic solvents having a boiling point at ordinary pressure of not higher than 100xc2x0 C., such as ethanol, acetone. One or more of those solvents may be used either singly or in combination, i.e., solvent mixtures may be used.
The amount of the solvent in the antibacterial primer may generally fall between 50% by weight and 99.999999% by weight, preferably between 70% by weight and 99.9999% by weight, more preferably between 90% by weight and 99.99% by weight, based on the total weight of the primer. These ranges include all specific values and subranges therebetween, such as 60, 75, 80, 85, 90, 95, 99, and 99.9% by weight, based on the total weight of the primer.
In some embodiments, it is often desirable to add polymerization initiator to the antibacterial primer which comprises an antibacterial polymerizable monomer and a volatile solvent such as those noted above, for the purpose of more firmly curing the antibacterial polymerizable monomer. The polymerization initiator is not specifically limited, and may be any inhibitor well-known to those skilled in the art.
Photopolymerization initiators may be used, including, for example, xcex1-diketone/reducing agent, ketal/reducing agent, thioxanthone/reducing agent, etc. Examples of the xcex1-diketone include camphorquinone, benzil, 2,3-pentanedione, etc. Examples of the ketal include benzyldimethyl ketal, benzyldiethyl ketal, etc. Examples of the thioxanthone include 2-chlorothioxanthone, 2,4-diethylthioxanthone, etc. Examples of the reducing agent include tertiary amines such as 2-(dimethylamino)ethyl methacrylate, N,N-bis[(meth)acryloyloxyethyl]-N-methylamine, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, butoxyethyl 4-dimethylaminobenzoate, N-methyldiethanolamine, 4-dimethylaminobenzophenone, dimethylaminophenanthol, etc., aldehydes such as dimethylaminobenzaldehyde, terephthalaldehyde, etc.; thiol group-having compounds such as 2-mercaptobenzoxazole, decanethiol, 3-mercaptopropyltrimethoxysilane, thiobenzoic acids etc. For photopolymerization through UV exposure, preferable examples include benzoin alkyl ethers, benzyldimethyl ketal, etc.
Also preferably used are acylphosphine oxide compounds, which include, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, benzoyldi-(2,6-dimethylphenyl) phosphonate, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, as well as water-soluble acylphosphine oxides such as those disclosed in JP-B-3-57916. These acylphosphine oxide compounds may be used either singly or as combined with a reducing agent of, for example, various amines, aldehydes, mercaptans, salts of sulfinic acids, etc.
One or more of these photopolymerization initiators and reducing agents may be used herein, i.e., mixtures may be used. The amount of the photopolymerization initiator and the reducing agent in the antibacterial primer may generally fall between 0.01% by weight and 20% by weight, preferably between 0.01% by weight and 10% by weight, more preferably between 0.1% by weight and 5% by weights based on the total weight of the antibacterial primer. These ranges include all specific values and subranges therebetween, such as 0.02, 0.05, 1, 2, 5, 10 and 15% by weight, based on the total weight of the antibacterial primer.
Chemical polymerization initiators are also employable herein, which are preferably redox polymerization initiators. Where such a redox polymerization initiator is used for the antibacterial primer which constitutes the bonding composition of the invention, the antibacterial primer should be divided into at least two parts which are separately wrapped or packaged and which separately contain either one of the oxidizing agent and the reducing agent for the initiator. However, in practical use of the antibacterial bonding composition of the invention, the antibacterial primer shall be all the time combined with the other constituent component of the adhesive component. Therefore, in the composition, the oxidizing agent and the reducing agent for the initiator may be separately incorporated into the antibacterial primer and the adhesive component.
The oxidizing agent may be an organic peroxide, including, for example, diacyl peroxides, peroxy esters, dialkyl peroxides, peroxy ketals, ketone peroxides, hydroperoxides, etc. Specific examples of the diacyl peroxides include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-toluoyl peroxide, etc.
The peroxy esters include, for example, t-butylperoxy benzoate, bis-t-butylperoxy isophthalate, 2,5-dimethy-2,5-bis(benzoylperoxy)hexane, t-butylperoxy 2-ethylhexanoate, t-butylperoxyisopropyl carbonate, etc.
The dialkyl peroxides include, for example, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, etc.
The peroxy ketals include, for example, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, etc.
The ketone peroxides include, for example, methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl acetacetate peroxide, etc.
The hydroperoxides include, for example, t-butylhydroperoxide, cumenehydroperoxide, p-diisopropylbenzeneperoxide, etc. One or more these oxidizing agents may be used either singly or as combined.
As the reducing agent, preferred are aromatic tertiary amine, aliphatic tertiary amines, as well as sulfinic acids, and salts thereof.
The aromatic tertiary amines include, for example, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine, N,N-diethyl-p-toluidine, N,N-dimethyl-3,5-dimethylaniline, N,N-dimethyl-3,4-methylaniline, N,N-dimethyl-4-ethylaniline, N,N-dimethyl-4-t-propylaniline, N,N-dimethyl-4-t-butylaniline, N,N-dimethyl-3,5-di-t-butylaniline, N,N-di(2-hydroxyethyl)-p-toluidine, N,N-di(2 hydroxyethyl)-3,5-dimethylaniline, N,N-di(2-hydroxyethyl)-3,4-diethylaniline, N,N-di(2-hydroxyethyl)-4-ethylaniline, N,N-di(2-hydroxyethyl)-4-i-propylaniline, N,N-di(2-hydroxyethyl)-4-t-butylaniline, N,N-di(2-hydroxyethyl)3,5-di-i-propylaniline, N,N-bis(2-hydroxyethyl)-3,5-di-t-butylaniline, ethyl 4-dimethylamonobenzoate, n-butoxyethyl 4-dimethylaminobenzoate, (2-methacryloyloxy)ethyl, 4-dimethylaminobenzoate, etc.
The aliphatic tertiary amines include, for example, trimethylamine, triethylamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-n-butyldiethanolamine, N-lauryldiethanolamine, triethanolamine, (2-dimethylamino)ethyl methacrylate, N-methyldiethanolamine dimethacrylate, N-ethyldiethanolamine dimethacrylate, triethanolamine monomethacrylate, triethanolamine dimethacrylate, triethanolamine trimethacrylate, etc.
The sulfinic acids end their salts include, for example, benzenesulfinic acid, sodium benzenesulfinate, potassium benzenesulfinate, calcium benzenesulfinate, lithium benzenesulfinate, toluenesulfinic acid, sodium toluenesulfinate, potassium toluenesulfinate, calcium toluenesulfinate, lithium toluenesulfinate, 2,4,6-trimethylbenzenesulfinic acid, sodium 2,4,6-trimethylbenzenesulfinate, potassium 2,4,6-trimethylbenzenesulfinate, calcium 2,4,6-trimethylbenzenesulfinate, lithium 2,4,6-trimethylbenzenesulfinate, 2,4,6-triethylbenzenesulfinic acid, sodium 2,4,6-riethylbenzenesulfinate, potassium 2,4,6-triethylbenzenesulfinate, calcium 2,4,6-triethylbenzenesulfinate, 2,4,6-i-propylbenzenesulfinic acid, sodium 2,4,6-i-propylbenzenesulfinate, potassium 2,4,6-propylbenzenesulfinate, calcium 2,4,6-i-propylbenzenesulfinate, etc.
One or more of these reducing agents may be used either singly or in combination.
The amount of the oxidizing agent and the reducing agent in the bonding composition of the invention may generally fall between 0.0001% by weight and 20% by weight, preferably between 0.01% by weight and 10% by weight, more preferably between 0.1% by weight and 5% by weight, based on the total weight of the antibacterial primer that constitutes the compositions. These ranges include all specific values and subranges therebetween, including 0.001, 0.2, 0.5, 1, 2, 10 and 15% by weight, based on the total weight of the antibacterial primer.
The antibacterial primer of the invention may optionally contain inorganic acids such as phosphoric acid, nitric acid, etc., organic acids such as maleic acid, citric acid etc., as well as polymerization inhibitors, antioxidants, UV absorbents, pigments, dyes and other additives, in addition to the components described above. Any additional polymerizable monomer may also be incorporated into the antibacterial primer, so long as it does not significantly interfere with the antibacterial capabilities of the primer. The amount of the additional polymerizable monomer, if any, in the antibacterial primer is generally at most 30% by weight, preferably at most 10% by weight, based on the total weight of the antibacterial primer. A fluorine compound having anticarious capabilities, such as sodium fluoride, may also be incorporated in the primer.
The antibacterial primer of the invention may also contain a filler. The filler may be any of organic, inorganic or even composite fillers. The inorganic fillers include, for example, silica, silica-based minerals such as kaolin, clay, mica, eta.; and silica-based ceramics and glass additionally containing any of Al2O3, B2O3, TiO2, ZrO2, BaO, La2O3, SrO2, CaO, P2O5, etc. Especially preferred are lanthanum glass, barium glass, strontium glass, soda glass, lithium borosilicate glass, zinc glass, fluoroaluminium borosilicate glass, borosilicate glass, bioglass, etc. Also preferred are crystalline quartz, hydroxyapatite, alumina, titanium oxide, yttrium oxide, zirconia, calcium phosphate, barium sulfate, aluminium hydroxide, etc.
The organic fillers may be an organic resin, including, for example, polymethyl methacrylate, polymers of polyfunctional methacrylates, polyamides, polystyrenes, polyvinyl chloride, chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc.
Also useful herein are inorganic/organic composite fillers, which may be prepared by dispersing an inorganic filler in an organic resin, or by coating an inorganic filler with an organic resin.
If desired, the fillers may be previously subjected to surface treatment with any known surface-treating agent such as a silane coupling agent or the like. The surface-treated fillers are effective for controlling the fluidity of the antibacterial primer and for enhancing the dispersibility thereof. The surface-treating agent includes, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltri(xcex2-methoxyethoxy)silane, xcex3-methacryloyloxypropyltrimethoxysilane, xcex3-glycidoxypropyl-trimethoxysilane, xcex3-mercaptopropyltrimethoxysilane, and aminopropyltriethoxysilane.
One or more those fillers may be used either singly or as combined. The amount of the filler, if any, in the antibacterial primer is generally at most 30% by weight, preferably at most 10% by weight, based on the total weight of the primer. As the filler, more preferred is colloidal silica having a mean particle size of at most 0.1 xcexcm.
The acid group-containing polymerizable monomer in the adhesive composition of the invention is a polymerizable monomer which contains at least one acid group. For example, the acid group may be a phosphoric acid residue, a pyrophosphorio acid residue, a thiophosphoric acid residue, a carboxylio acid residue, a sulfonic acid residue or the like, and has a polymerizable unsaturated group of, for example, an acryloyl group, a methacryloyl group, a vinyl group, a styrene group or the like. Specific examples of the monomer are described below. The terminology xe2x80x9c(meth)acrylxe2x80x9d as used herein includes both xe2x80x9cmethacrylxe2x80x9d and xe2x80x9cacrylxe2x80x9d.
The polymerizable monomers having a phosphoric acid residue include, for example, 2-(meth)acryloyloxyethyl dihydrogenphosphate, 4-(meth)acryloyloxybutyl dithydrogenphosphate, 6-(meth)acryloyloxyhexyl dihydrogenphosphate, 8-(meth)acryloyloxyoctyl 9-(meth)acryloyloxynonyl dihydrogenphosphate, 10-(meth)acryloyloxydecyl dihydrogenphosphate, 11-(meth)acryloyloxyundecyl dihydrogenphosphate, 20-(meth)acryloyloxyeicosyl dihydrogenphosphate, 1,3-di(meth)acryloyloxypropyl-2-dihydrogenphosphate, dihydrogenghosphate, 2-(meth)acryloyloxyethylphenyl phosphate, 2-(meth)acryloyloxyethyl-2xe2x80x2-bromoethyl phosphate, (meth)acryloyloxyethylphenyl phosohonate, and their acid chlorides.
The polymerizable monomers having a pyrophosphine acid residue include, for example, di(2-(meth)acryloyloxyethyl) pyrophosphate, di(2-(meth)acryloyloxybutyl) pyrophosphate, di(2-(meth)acryloyloxybexyl) pyrophosphate, di(2-(meth)acryloyloxydecyl) pyrophosphates, and their acid chlorides.
The polymerizable monomers having a thiophosphoric acid residue include, for example, 2-(meth)acryloyloxyethyl dihydrogendithiophosphate, 10-(meth)acryloyloxydecyl dihydrogendithiophosphate, and their acid chlorides.
The polymerizable monomers having a carboxylic acid residue include, for example, maleic acid, maleic anhydride, 4-(meth)acryloyloxyethoxycarbonylphthalic acid, 4-(meth)acryloyloxyethoxycarbonylphthalic anhydride, 5-(meth)acryloylaminopentylcarboxylic acid, 11-(meth)aryloyloxy-1,1-undecanedicarboxylic acid, and their acid chlorides.
The polymerizable monomers having a sulfonic acid residue may be compounds having a sulfonic acid group, such as, for example, 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, 2-sulfoethyl(meth)acrylate, etc.
One or more those acid group-containing polymerizable monomers may be used herein either singly or in combination, i.e., mixtures of different acid group-containing monomers may be used.
The amount of the acid group-containing polymerizable monomer in the adhesive component may generally fall between 0.1% by weight and 80% by weight, preferably between 1% by weight and 60% by weight, based on the total weight of the adhesive composition. These ranges include all specific values and subranges therebetween, such as 0.02, 0.05, 2, 5, 10, 25, 50 and 75% by weight, based on the total weight of the adhesive composition.
Examples of the other polymerizable monomer which is also in the adhesive composition include, esters of xcex1-cyanoacrylic acid, (meth)acrylic acid, xcex1-halogenoacrylic acids, crotonic acid, cinnamic acid, sorbic acid, maleic acid, itaconic acid and the like; as well as (meth)acrylamide, (meth)acrylamide derivatives, vinyl esters, vinyl ethers, mono-N-vinyl derivatives, styrene derivatives, etc. Of those, (meth)acrylates are preferred. Examples of the polymerizable monomers are described below.
The terminology xe2x80x9cmonofunctional monomerxe2x80x9d as referred to herein means to indicate a monomer haying one olefinic double bond.
(i) Monofunctional Monomers
These include, for example, methyl (methacrylate, iso-butyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, 2-(N,N-dimethylamino)ethyl (meth)acrylate, 2,3-dibromopropyl (meth)acrylate, 3-methacryloyloxypropyltrimethoxysilane, 2-hydroxyethyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, propylene glycol mono(meth)acrylate, glycerin mono(meth)acrylate, erythritol mono(meth)acrylate, N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N,N-(dibydroxyethyl)(meth)acrylamide, (meth)acryloylaxydodecylpyridinium bromide, (meth)acryloyloxydodecylpyridinium chloride, (meth)acryloyloxyhexdodecylpyridinium bromide, (meth)acryloyloxyhexdodecylpyridinium chloride.
(ii) Difunctional Monomers
These include, for example, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, bisphenol A diglycidyl(meth)acrylate, 2,2-bis[4-(meth)acryloyloyethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxypolyethoxyphenyl]propane, 2,2-bis [4-[3-(meth)acryloyloxy-2-hydroxypropoxy]phenyl]propane, 1,2-bis[3-(meth)acryloyloxy-2-hydroxypropoxy]ethane, pentaerythritol di(meth)acrylate, 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethane, [2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)] dimethacrylate.
(iii) Trifunctional or Higher Polyfunctional Monomers
They include, for example, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, N,Nxe2x80x2-(2,2,4, trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol] tetramethacrylate, 1,7-diacryloyloxy-2,2,6,6-tetracryloyloxymethyl-4-hydroxyheptane.
One or more of these polymerizable monomers may be used either singly or in combination.
The amount of the polymerizable monomer in the adhesive composition may generally fall between 5 and 95% by weight, preferably between 30 and 90% by weight, more preferably between 40 and 80% by weight, based on the total weight of the adhesive component. These ranges include all specific values and subranges therebetween, such as 10, 15, 20, 25, 50, 75 and 90% by weight, based on the total weight of the adhesive component.
The polymerization initiator in the adhesive composition is important for curing both the adhesive component and the antibacterial primer, and is not particularly limited. Any of the well-known polymerization initiators known may be used in the present invention. The polymerization initiator may be any of the well-known photopolymerization initiators and/or chemical polymerization initiators.
For the photopolymerization initiators usable in the adhesive component, examples include those described above for the antibacterial primer. The same initiator in the antibacterial primer mentioned hereinabove may also be in the adhesive component. Especially preferred for the adhesive component is a combination of xcex1-diketone/acylphosphine oxide/reducing agent.
One or more photopolymerization initiators and also reducing agents may be used either singly or as combined. The amount of the photopolymerization initiator and the reducing agent in the adhesive composition may generally fall between 0.01 and 20% by weight, preferably between 0.1 and 5% by weight, based on the total weight of the adhesive composition. These ranges include all specific values and subranges therebetween, such as 0.02, 0.05, 0.2, 0.5, 1, 2, 8, 10 and 15% by weight, based on the total weight of the adhesive composition.
When the adhesive composition of the invention will be exposed to the ambient light, the composition should be protected from being thickened, gelled or cured owing to the ambient light within a short period of time. For this purpose, it is desirable that the total amount of the acylphosphine oxide compound and the xcex1-diketone compound is limited to fall between 1% by weight and 6% by weight. More preferably, the ratio of the acylphosphine oxide compound to the xcex1-diketone compound in the adhesive composition is so defined that the latter is from 0.01 parts by weight to 0.5 parts by weight based on one part by weight of the former. In the ratio defined above, the adhesive composition is stable even in the ambient light and its photocurability is high.
Chemical polymerization initiators are also employable herein, which are preferably redox polymerization initiators. Where such a redox polymerization initiator is used for the adhesive composition, the adhesive composition must be divided into at least two parts which are separately wrapped or packaged and which separately contain either one of the oxidizing agent and the reducing agent for the initiator. However, where the adhesive composition is combined with the antibacterial primer described above to constitute the antibacterial bonding compositions of the invention, any one of the oxidizing agent and the reducing agent for the initiator may be incorporated in either the antibacterial primer or the adhesive composition. In that case, the adhesive composition may be in the form of a single package.
For the oxidizing agents and the reducing agents usable in the adhesive composition, examples include those described above for the antibacterial primer. The same initiator in the antibacterial primer may also be in the adhesive composition.
One or more oxidizing agents and reducing agents may be used either singly or as combined. The amount of the oxidizing agent and the reducing agent to be in the adhesive component may generally fall between 0.01 and 20% by weight, preferably between 0.1 and 10% by weight, based on the total weight of the adhesive composition. These ranges include all specific values and subranges therebetween, such as 0.02, 0.05, 0.2, 0.5, 1, 2, 5 and 15% by weight, based on the total weight of the adhesive composition.
The adhesive composition in the invention optionally contain a filler, which is for improving the handlability, the coatability and the mechanical strength of the composition. For examples of the filler, referred to are those of inorganic fillers, organic fillers, inorganic/organic composite fillers mentioned hereinabove for the antibacterial primer. The same filler as in the antibacterial primer mentioned hereinabove could also be in the adhesive composition.
One or more such fillers may be used either singly or as combined. The amount of the filler, if any, in the adhesive composition is generally at most 70% by weight, preferably at most 50% by weight, based on the total weight of the adhesive composition. Where the adhesive composition contains an organic solvent or water, the amount of the filler therein is preferably at most 30% by weight. As the filler, especially preferred is colloidal silica having a mean particle size of at most 0.1 xcexcm.
The adhesive composition in the invention may optionally contain polymerization inhibitors, antioxidants, UV absorbents, pigments dyes and other additives in addition to the ingredients noted above. A fluorine compound having anticarious capabilities, such as sodium fluoride, may be incorporated in the adhesive composition.
Preferably, the adhesive composition of the present invention is divided into plural parts, for example, as a combination of an adhesive primer and a bonding agent, or a combination of an adhesive primer and a resin cement. The adhesive composition that is in the form of such combinations is preferred, because its bonding strength to tooth is greatly increased. More preferably, the divided parts of the adhesive composition selectively contain specific ingredients, as mentioned below.
(A) Adhesive Primer
Preferably, the adhesive primer comprises an acid group containing polymerizable monomer such as those described above (in an amount of from 5% by weight to 50% by weight), a hydrophilic polymerizable monomer having a solubility in water at 25xc2x0 C. of at least 5% (in an amount of from 20% by weight to 95% by weight), and water (in an amount of from 5% by weight to 70% by weight). Comprising these components, the adhesive primer exhibits improved penetrability into teeth and also improved adhesiveness to teeth.
More preferably, the adhesive primer also contains a polymerization initiator (in an amount of from 0.1 to 5% by weight).
For specific examples of the constituent ingredients in the adhesive primer, examples include those described above. In particular, as the hydrophilic polymerizable monomer, preferred are 2-hydroxyethyl methacrylate, 3-hydroxypropoylmethacrylate, polyethylene glycol dimethacrylate in which the number of oxyethylene groups is at least 9).
(B) Bonding Agent
The bonding agent comprises a polymerizable monomer and a polymerization initiator, to further enhance the curing of the antibacterial primer and also the adhesive primer noted above (these primers are applied to a tooth prior to the bonding agent), thereby increasing the bonding strength of the adhesive composition of the invention to a tooth. More preferably, the bonding agent contains an acid group-containing polymerizable monomer such as that mentioned above (in an amount of from 1% by weight to 30% by weight) and/or a filler (in an amount of from 1% by weight to 30% by weight). The polymerization initiator in the bonding agent is preferably a photopolymerization initiator.
In the adhesive composition of the invention, in which the adhesive composition is divided into two parts of an adhesive primer and a bonding agent, the photopolymerization initiator in the bonding agent is preferably a combination of an acylphosphine oxide compound and an xcex1-diketone compound.
In the preferred embodiment, the adhesive primer and the bonding agent can be firmly cured within a short period of time to give a cured product having increased bonding strength, especially increased bonding durability.
The acylphosphine oxide compounds include, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-diethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, benzoyldi-(2,6-dimethylphenyl) phospbonate, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, as well as water-soluble acylphosphine oxides such as those disclosed in JP-B-3-57916.
The xcex1-diketone compounds include, for example, camphorquinone, benzil, and 2,3-pentanedione.
The amount of the acylphosphine oxide compound in the bonding agent may generally fall between 0.5% by weight and 10% by weight, preferably between 1% by weight and 7% by weight, more preferably between 2% by weight and 5% by weight, based on the total weight of the bonding agent. The amount of the xcex1-diketone compound to be in the bonding agent may generally fall between 0.01% by weight and 5% by weight, preferably between 0.05% by weight and 3% by weight, more preferably between 0.1% by weight and 1.5% by weight, based on the total weight of the bonding agent.
In general, the acylphosphine oxide compounds and the xcex1-diketone compounds are combined with a reducing agent of, for example, amines, aldehydes, mercaptans or salts of sulfinic acids, as their ability to promote photopolymerization reaction is enhanced. For specific or preferred examples of the reducing agent, referred to are those mentioned hereinabove. The amount of the reducing agent to be in the bonding agent may generally fall between 0.5% by weight and 10% by weight, preferably between 0.1% by weight and 5% by weight, based on the total weight of the bonding agent.
When the bonding agent of the invention will be exposed to the ambient light, the bonding agent is preferably protected from being thickened, gelled or cured owing to the ambient light within a short period of time. For this purpose, it is desirable that the total amount of the acylphosphine oxide compound and the xcex1-diketone compound in the bonding agent is limited to fall between 1% by weight and 6% by weight. More preferably, the ratio of the acylphosphine oxide compound to the xcex1-diketone compound in the bonding agent is so defined that the latter is from 0.01 parts by weight to 0.5 parts by weight based on one part by weight of the former. In the defined ratio, the bonding agent is stable even in the ambient light and its photocurability is high.
If desired, the bonding agent may further contain any other photopolymerization initiators and/or chemical polymerization initiators, in addition to the acylphosphine oxide compound and the xcex1-diketone compound. For examples of the chemical the photopolymerization initiators and polymerization initiators, referred to are those mentioned hereinabove.
(C) Resin Cement
The resin cement comprises a polymerizable monomer, a polymerization initiator and a filler, and this is for further enhancing the curing of the antibacterial primer and also the adhesive primer thereby to increase the bonding strength of the adhesive composition of the invention to a tooth and also to increase the abrasion resistance of the resin cement itself. More preferably, the resin cement contains an acid group-containing polymerizable monomer such as that mentioned above (in an amount of from 1% by weight to 20% by weight), as the monomer is effective for much more enhancing the bonding strength of the composition of the invention. The amount of the filler to be in the resin cement is preferably from 40%, by weight to 80% by weight. As the filler, preferred is an X-ray opaque material, such as barium glass.
The adhesive composition of the invention is used in such a manner that the antibacterial primer in the compositions is first applied to the surface of a tooth, then the adhesive composition is applied on it, and the two are cured thereon. Specific examples of using the adhesive composition are described below, which, however, are not limitative.
(1) Direct Restoration and Repairing with Composite Resin
The antibacterial primer of the invention is applied to the cavity formed in a tooth. Then, this is left as such or forcedly dried with a dental air syringe to remove the volatile solvent. Next, the adhesive composition of the intention is applied on this, and left as such for a while, or it desired, the coated area is blown with a dental air syringe. In that condition, the ingredients in the coated area are cured. Where the adhesive composition is composed of two divided parts of an adhesive primer and a bonding agent, the adhesive primer is first applied to the intended area, then left as such for a predetermined period of time, and thereafter subjected to air blowing. Next, the bonding agent is applied to that area, and the ingredients are cured. The curing may be effected in any desired manner of photopolymerization, a chemical polymerization or dual curing of photopolymerization and chemical polymerization (hereinafter photo/chemical polymerization). Preferred is photopolymerization for which is used an irradiator, or dual curing polymerization, as being easy to perform.
After the adhesive composition has been cured, composite resin or composition for dental restoration is added to the cured area and then cured. By this treatment, the restoration of the tooth is completed.
(2) Indirect Restoration and Repairing with Prosthetic Material
The antibacterial primer of the invention, is first applied to the cavity formed in a tooth. Then, this is left as such or forcedly dried with a dental air syringe to remove the volatile solvent.
Next, the adhesive composition of the invention is applied to a prosthetic material such as a metal alloy, a ceramic, a cured composite resin or the like, which is then pressed against the surface of the tooth having been previously the treated with the antibacterial primer, and then cured. Through the treatment, the restoration of the tooth is completed. In this case, the adhesive composition may be applied to the antibacterial primer-coated surface of the tooth.
Where the adhesive composition is composed of two divided parts of an adhesive primer and a resin cement, the adhesive primer is first applied to the surface of the tooth having been previously treated with the antibacterial primer, then left as such for a predetermined period of time, and thereafter subjected to air blowing. Next the prosthetic material is applied to the treated surface of the sooth along with the resin cement, and cured and bonded to the tooth, The curing may be effected in any desired manner of photopolymerization, chemical polymerization or dual curing of photo/chemical polymerization. In this case, however, the light, from the irradiator for photopolymerization will be often blocked by the prosthetic material. Therefore, for curing the adhesive composition (end also the resin cement) in this case, preferred is chemical polymerization or dual curing polymerization.
In addition, the bonding compositions for dental use of the invention may also be combined with any other bonding ingredients of glass ionomer cement, zinc phosphate cement, polycarboxylate cement, silicate cement, zinc oxide eugenol cement; and also with heat-curable resin, self-curable resin, root canal filler, or temporary sealant.
In particular, for repairing the restorative material having been broken in the mouth, the adhesive compositions of the invention may be applied not only to the tooth restored with the material but also to the repairing material of metals, ceramics or cured composite resins. Further, in their use, the bonding compositions of the invention may be combined with any commercially-available acid etchants or tooth surface cleaners such as hypochlorites, etc.